Knocking/Tapping noise when cold 4eFte

[telmodmc]

HI mates,

I have a glanza V manual it's is stock, just install a Dump Valve nothing more.

When I start my car and acelerate a litle I hear a knocking / tapping noise that comes from the engine.

But this noise just make when the engine it's cold or in the first 400m when i drive, than the noise stops. What could it be ?

I talked with friends, 1 told me it could be the oil pressure, but i think if was the oil pressure when i went to high rpm it have to make it again, but my car don't do it. other said me it could be the manifold cracked, but now i don't know what to do because i don't know wheres commig the tapping noise.

Please, someone have an idea ??

Regards,

Telmo Costa